Automatic calibration for wobble errors in shallow water multibeam bathymetries

The wobble errors caused by the imperfect integration of motion sensors and transducers in multibeam echo-sounder systems (MBES) manifest as high-frequency wobbles in swaths and hinder the accurate expression of high-resolution seabed micro-topography under a dynamic marine environment. There are many types of wobble errors with certain coupling among them. However, those current calibration methods ignore the coupling and are mainly manual adjustments. Therefore, we proposed an automatic calibration method with the coupling. First, given the independence of the transmitter and the receiver, the traditional georeferenced model is modified to improve the accuracy of footprint reduction. Secondly, based on the improved georeferenced model, the calibration model associated with motion scale, time delay, yaw misalignment, lever arm errors, and soundings is constructed. Finally, the genetic algorithm (GA) is used to search dynamically for the optimal estimation of the corresponding error parameters to realize the automatic calibration of wobble errors. The simulated data show that the accuracy of the calibrated data can be controlled within 0.2% of the water depth. The measured data show that after calibration, the maximum standard deviation of the depth is reduced by about 5.9%, and the mean standard deviation of the depth is reduced by about 11.2%. The proposed method has significance in the precise calibration of dynamic errors in shallow water multibeam bathymetries.